Prior art will be described. At the outset, thiazoles having a trifluoromethanesulfonylamino group at the 2-position are described in U.S. Pat. Nos. 3,923,810 and 3,923,811. Japanese Pat. Appln. Laid-Open Gazettes Nos. Sho 64-40474 (40474/89) and Sho 64-75475 (75475/89) describe thiazole derivatives having anti-inflammatory action and analgesic action. Phenyl pivalate derivatives are described as an elastase inhibitor in U.S. Pat. No. 4,801,610 and Japanese Pat. Appln. Laid-Open Gazette No. Hei 3-20253 (20253/91). Further, the compounds or part of the compounds of this invention are described also in Japanese Pat. Appln. Laid-Open Gazettes Nos. Hei 3-173876 (173876/91) and Hei 5-70446 (70446/93). However, the antibacterial action or bactericidal action of the compounds of this invention is not disclosed at all, nor is it suggested.